Electric blasting cap package and method of forming the same



Dec. 4, 1934. D. M. M FARLAND 1,983,141

ELECTRIC BLASTING CAP PACKAGE AND METHOD OF FORMING THE Filed March 1'7, 1933 I MENTOR I DAVIDMM FARLANmp ATTO RN EY Patented Dec. 4, 19 34 ELECTRIC BLASTING CAP PACKAGE AND NIETHOD F FORMING THE SALE w David M. McFarland, West Chester, n.1-

to Atlas Powder Company, W

ilmlngton, Del...

a corporation of Delaware I Application March 17, 1933, Serial No. 851,397

This invention relates to an electric blasting cap package and method of forming the same. It is well known that the blasting caps or electric blasting caps commonly employed for initiating the explosion of dynamite and other high explosives, which are detonated by concussion, are quite sensitive to mechanical shock, and many accidents, with resultant serious loss of life and damage to property,.have occurred during the 9 preliminary handling of such detonators.

It is a primary object of thepresent invention to so form an electric blasting cap' package that a maximum ofsafety may be achieved during 7 handling or shipment, and a maximum of convenience may be had in practical use of the electric blasting cap. The means by which these objects are achieved will be more specifically de-, scribed in connection with the accompanying drawing wherein: Figure 1 isa perspective view showing the manner of folding the leg wires.

Figure 2 is a perspective view showing the detonator and battery ends of the-wire folded over upon the loops of the wires. Figure 3 is a perspective view showing the loops partly folded about the detonator to house and enclose the same.

Figure 4 is a perspective view of the complete package.

Figure6 is aperspective view showing the housing tube'of Fig. 4 broken along a weakened central line so that it may. be readily stripped in opposite directions endwise from the wire bundle.

Figure 7 is a detail view illustrating the manner in which the leg wiresmay be drawn out without tangling.

Like numerals designate corresponding parts in all the figures of the drawing.

40 It is common practice in the folding 'of the leg wires of electric blasting caps to fold said. wires to figure 8 form and in the formation of the present electric blasting cap package, I preferably follow that practice with the addition of certain. I refinements that will be hereinafter described.

Ordinarily no special effort has been made by manufacturers in folding the leg wires of electric blasting caps to figure 8 form to fold-the wires with a. transverse motion so that the loops are all of the same length, and are formed one after the other, as illustrated in Figure 1, without permitting any portions of said loopsto overlap the others. By this method of folding the full value of the figure 8 fold isobtained, the folds tending to spring apart as the support is removed from the bundle. when in this condition the wires can-be straightened with no tangling whatsoever.

This favorable action cannot be accomplished consistently with the figure 8 fold now in general do use, which is not carefully formed to prevent one Figure 5 is an end view of thecomplete package;

16 Claims. (01. 102 -10).

loop from overlapping another. Therefore, by the term progressive loop formation, as hereina-fter used, I mean loops which successively lie essentially in advance of and in non-intertwined relation to preceding loops.

The detonator is illustrated at 6 and is attached to one end of the pair of insulated leg wires 5, 5' while the opposite ends of said wires are scraped bare of insulation, as indicated at 7 and 8, and these bare portions are preferably joined adjacent to the insulation by a small metallic shunt or clip 9.- This also is in common use and is for the purpose of guarding against explosion of the detonator 6 if either of the bared ends 7 and 8 should accidentally come in con- In Fig. 'l, the

tactwith a source of E. M. F. body portions of the wires 5, 5' are indicated by heavier lines than are the ends 7 and 8 forthe purpose of distinguishing between the insulated portions of these two separate wires and the bared ends '7 and 8 thereof. After a desired number of loops or convolutions 5 have been formed, the detonatorand the battery ends 7 and 8 are folded over upon said loops, as illustrated inFig. 2, and then the loops of the bunch or group are folded around the detonator, aspartly'illustrated in Fig. 3, until the said detonator and the bared ends 7 and g 8 are housed within the folds or loops. Then the bundle of wire constituted by said loops, together with-the detonator, is preferably thrust endwise into a suitable protecting tube 9. This may be a simple paper or cardboard tube, and I preferably weaken it circumferentially at a central point, indicated at 10, by scoring, so

that when it is desired to use the detonator thetube may be broken, as indicated in Fig. 6, by bending itfirst in one direction and then in the other, after which the ends of said tubes may be readily stripped endwise from the bunch of wires. It will be understood that the terms blasting cap and detonator are synonymous; these names being commonly interchangeably used in the art. Electric squibs are very similar in external form .to electric blasting caps in, that they usually comprise a relatively small elongated metallic shell of copper, gilding metal, aluminum, or the like, together with attached wires for setting oif the shell contained charge. It will be obvious that my improved packaging method may be used for squibs as readily as for detonators,

and I wish it tobe understood that the term detonator isto be broadly construed, both in the specification and in the attached claims.

While I prefer to use a tube, such as 9,which will completely house the wire loops of the detonator, it is within the purview of the invention to use a shorter tube than that shown, or any equivalent band of material which will encircle fully or in part the bundle of wire. For ex- 'ample, it would be possible, though not so desirable, to tie the loops either at the central portion alone or at several points in the length of the bundle, it being apparent that ties are the equivalents of -bands as far as holding the loops in position, is concerned and may, if desired, consist of winding the loose ends of the leg wires, themselves, about the bundle, in a manner commonly employed heretofore in the shipment of electric detonators.

The present inventive thought involves materially more than merely folding wire back and forth along the detonator and then thrusting the whole into a containing casing in that the following important features are inherent in the present arrangement:

1. The loops are bent back and forth with respect to each other but are not interwoven in such manner as to cause tangling when it is attempted to straighten them out. By referring to Fig. 7, it will be seen that the successive loops there shown have difierent major axes. By virtue of this, when the loops are thrust toward each other to make the compact bundle of Fig. 3, each loop lies in separated relation to every other loop in the sense that there is no such interweaving of the loops with each other as to cause tangling when it is attempted to draw the leg wires out into an elongated strand. It is further to be observed that the loops are all of substantially the same length. This aids in preventing tangling because it is apparent that if one loop were materially shorter than the other, its ends could easily project through adjacent loops and become entangled with the same. I prevent this by making the loops of substantially uniform length.

2. The loops are so formed that their rounded end portions 5a have a certain degree of resiliency or spring action with the result that when these resilientelements are compressed and thrust into a retaining tube 9 their resiliency not only holds them securely in the tube but, which is more important, when the tube is broken and stripped from the wires, as described, the package immediately springs, of itself, to open position, exposing the detonator and battery ends.

If the miner, or blaster, or other operative then pulls out only one or two loops at the detonator end of the wires for attachment to a cartridge of dynamite, the remainder of the package retains its shape and holds the bare ends of the wires from dropping upon the ground or into contact with any conductors-which might constitute a source of danger to the same. However, just as soon as the detonator has been fastened in the cartridge of dynamite, a mere straight line pull upon the wires from" the bare ends causes the wires to immediately straighten out to their full length, without kinking or tangling, or the leaving of undesirable bends in their length. The wire acts much like the folds of an accordion; the several folds tending to spring apart when released from the restraint imposed thereon by the tube 9. I may-seal the ends of the tube, if desired, witha .cap in much the same manner that a shotgun shell is closed by a wad, or, I may leave these ends open.

. There is another important advantage inherent in the present construction and that is that the described arrangement of wlreconstitutes a very powerful protecting means for the detonator in the event of accidental explosion of the latter.

Contrary to'a rather widely held idea,' the force of the explosion of a detonator is not only exerted laterally of the detonator but is also exerted end wise of the detonator. That this is so is shown by the fact that the accepted practice in testing detonators is to shoot them on end upon a lead plate and the degree to which the detonator effectually pierces said plate is the measure of the effectiveness of the detonator. Now, it will be seen that the described arrangement crowds a large number of bends of wire, indicated at 5a, into very close and intimate contact with each other at the opposite'ends of the tube 9 and that the mass of wire bends disposed adjacent the ends of the tube lie between the ends of the detonator and any person handling said detonator.

Consequently, the described arrangement is not .pnly highly desirable from the standpoint of convenience and use but it is highly effective from the standpoint of safety. The advantages of inserting the bundle of wires and detonator in a tube are as follows:

1. This arrangement supports the detonator and the battery ends in position in the bundle without the usual twisting'of these ends and consequent extra kinks and bends.

2. The tube protects the detonator within the bundle from mechanical injury.

'3. The tube, when made of proper material, eifectively insulates the cap electrically.

4. The tube serves as a means of labeling and describing the package and warning all persons of the dangerous nature of the same, and when broken in half, the parts are identified as those of an empty tube.

Further, this tube, when finished in highly contrasting colors, renders the package readily detected if misplaced or lost, or dropped in a relatively dark spot, as in a mine, or otherwise.

I wish it to be understood that the invention is not limited to the winding of the wire in the particular manner shown because other ways of winding the wire may be resorted to and still retain the advantages of the invention. Any method of winding, which insures against tangling and wherein the convolutions tend to spring apart and consistently separate themselves-from each other when the winding support is removed, will give'the result sought.

Further, while the tendency of the individual loops to spring apart or separate from each other, when released, is helpful, the winding in nonintertwined, and consequently non-tangling, formation is a feature of great importance whether the wire is resilient or not and whether the loops tend to spring apart under such resiliency or not. As far as I am aware I am the first to wind the wire constituting the leg wires of an electric detonator into the form of elongated loops, whether in figure 8 form, or otherwise, and wherein the wire of each loop is disposed in a plane of its own,

i. e., having no intertwined relation with respect to the wires of other loops; and folding a group of said loops about a detonator in such manner as to at least in part house said detonator therein, so that the wires serve as a protecting means for the detonator during shipment and as a. connecting means for the detonator when the time of use arrives. It is apparent that the number of loops to a given length of wire is determined by the length of the individual loops. While the maximum of protection is aiforded by having enough loops to substantially house the detonator, it is none the less a fact that a substantial measure of protection is afforded even though the loops are, by reason of their length, in insufilcient number to completely embrace the detonator, and it is also a fact that the placing of the detonator and the wires in a tube in the manner described is ofgreat utility in holding the wires in untangled relation and in holding the detonator in the proper place with respect to the wires, irrespective of the degree to which the detonator is embraced by the wires.

' Having described my invention, what I claim is: s

1. The herein described method of forming an electric blasting cap package comprising a detonator, its leg wires, and a container for the same, which consists of folding said wires back and forth in progressive loop formation and without interweaving of said loops, folding the said loops about 1 the detonator and forcing the bundle of loops with the contained detonator into the container, as described.

2. An electric 'blasting'cap package comprising a detonator and its leg wires folded to constitute a plurality of elongated, non-interwoven resilient loops, said loops being folded into bundle formation about the detonator, and a containing tube of such diameter that when the bundle is thrust therein said loops are thereby placed under tension.

. a containing tube, and a detonator and its leg wires, said leg wires being bent to form a plurality of progressive and non-intertangled loops extending longitudinally of the detonator and containing tube, the group of loops being bent to substantially circular bundle formation about 8. An electric blasting cap package compris-.

ing a detonator and its leg wires, said leg wires being bent to form a plurality of progressive and non-intertangled folds of substantially uniform. length extending longitudinally of the detonator,

the group of loops "being in such number that they may complementally substantially completely encircleand house the detonator, and a restraining means about said folds. v

9. The herein described method of assembling and packaging a detonator and its attached leg 7 wires which consists of bending the said leg wires to form a progressive succession of oblong loops having different axes, then bunching said loops in untangled relation and then folding 'a group of said loops about the detonator in such manner as to substantially completely encircle the same,

said loops being of such length as to project .beyond the opposite ends of the detonator, whereby the detonator is housed within the group of loops throughout its circumference and the ends of the loops house the ends of the detonator as described.

10. The herein described method of forming an .electric detonator package comprising a detonator and its leg wires, which consists of folding said leg wires into the form of a number of elongated and progressively advancing loops, bringing said loops together to cause them to constitute a bunch of loops, andnesting said detonator within said bunch of loops and applying a binding means circumferentially about the whole.

11. A detonator package comprising a detonator and its leg wires, the latter being bent to 'form a group of elongated loops of substantially uniform length which occupy progressively different and individual planes, said loops forming a bunch of loops within which the detonator is housed substantially throughout its length and circumference, said loops tending to spring away from the detonator and expose the same when released, and a containing tube of a size to receive the said detonator and its leg wires.

12. An electric detonator package comprising a detonator with its appended leg wires in the form of a series of oblong loops bound in substantially longitudinal parallelism with and close to and at least partially covering the surface of the said detonator; the said loops being substantially of equal length and at least as long as the detonator body and each loop being primarily bent to lie in a progressively different plane from that of the preceding loop so that said loops lie in non-intertwined and non-intersecting relation to each other. i

13. An electric detonator package as in claim 12 wherein the said leg wire loops are in figure 8 form.

14. A structure as recited in claim 8 wherein said folds are enough longer than the detonator to permit the ends of said folds to be brought together to completely enclose and house the ends of the detonaton' 15..An electric detonator package comprising a containing tube, a detonator and its appended leg wires in the form of a series of oblong loops, lying lengthwise of and close to, and at least partially covering the surface of .said detonator, each loop being primarily bent to be in a progressively different plane from that of the preceding loop so that sai loops lie in non-intertwined and non-intersectin relation to each other, the loops and detonator being disposed lengthwise within said tube, said tube holding the wires and detonator in the established relation until the time of use arrives.

16. The herein described method of assembling and packaging a detonator and its attached leg wires, which consists of folding the said leg I wires to formaprogressive succession of oblong tion to the detonator until the time of use arrives.

DAVID M. McFARLAND. 

